1. Field of the Invention
The present invention relates to vehicle lights, such as headlights and tail lights, that are used on the exterior of a vehicle. More particularly, the present invention relates to vehicle light assemblies that are comprised of an array of small lights and the structure of such assemblies.
2. Prior Art Description
Most modern motor vehicles have headlights that enable the vehicle to be driven at night. However, the design of headlights has evolved greatly over time. Initially, lights used on horse-drawn carriages and the earliest automobiles were open flame lamps. Open flame lamps were quickly replaced with electric headlights. The first electric headlights contained a single incandescent light bulb that was powered by the battery of the vehicle. Accordingly, the headlights could be turned either “on” or “off”. Eventually, incandescent bulbs were created for vehicles that contained two elements. One element was lit during normal driving condition and both elements were lit when a driver needed more light. Thus, a vehicle headlight could light in a low beam condition or a high beam condition.
A problem associated with headlights that use incandescent bulbs is the use of electrical power. Incandescent bulbs require a large flow of current. However, in modern automobile, electric current is becoming a scarce commodity. In modern automobiles, more and more electronic features are being added in each model year. The demand for more electricity has caused many vehicle manufacturers to increase the size and power of both the battery and the power alternator that are built into the vehicle. However, due to the small amount of space available in the engine compartment of a modern vehicle, the size of the vehicle battery and alternator also needs to be limited.
Recognizing the need to save energy, headlights for vehicles have been designed that used low power light emitting diodes (LEDs) rather than incandescent bulbs. Although a single LED cannot match the power of an incandescent headlight bulb, an array of LEDs can. Thus, vehicle headlights comprised of an array of LEDs have been designed. Such prior art LED headlights are exemplified by U.S. Patent Application Publication No. 2003/0147252 to Floravanti, entitled Front Lighting System For A Motor Vehicle.
Although LEDs use less power than conventional incandescent headlights, prior art LED headlights do have some disadvantages. One disadvantage is that LEDs must be mounted to a substrate that provides power to the LEDs. The substrate must be coupled to a heat sink or otherwise cooled in order to have the LED headlight last for the projected life of the vehicle. Furthermore, since the LEDs are affixed to a common substrate, all the LEDs in the array tend to be pointing in the same direction. As a consequence, the direction of the beam of light remains constant. The only way to produce a high beam condition and a low beam condition is to vary the intensity of the headlight by controlling the number of LEDs in the array that are lit. It is therefore difficult to create a discernable low beam condition and high beam condition.
Another disadvantage of LED headlights is the ability to vaporize condensed water. Water vapor often condenses within the structure of a headlight. A traditional incandescent headlight can quickly vaporize such condensation once the headlight is lit. Thus, the condensation has little effect on the performance of the headlight. However, an LED headlight uses an array of LEDs, a larger surface is available onto which condensation can form. Once the condensation forms on the various LEDs, the LEDs lack the power output needed to quickly vaporize the condensation. The result is that the condensation remains on the LEDs, distorting and diminishing the light emitted by the LEDs.
A need therefore exists for an improved structure of an LED headlight that has a well defined high beam and low beam. A need also exists for an LED headlight that eliminates the adverse effects of condensation forming on the LEDs. These needs are met by the present invention as described and claimed below.